A Synthetic Ion Channel Derived from a Metallogallarene Capsule That Functions in Phospholipid Bilayers

Biomimetic Approach for Ion Channels Based on Surfactant Encapsulated Spherical Porous Metal‐Oxide Capsules

“…Discussion of the results: It is important to note that the thickness of the insulating hydrophobic region of bilayer membrane (30–35 Å) is quite similar to the external diameter of the capsules 1a and 2a ( Figure ), while the hydrophobic interactions between the DODA + surfactants and the bilayer stabilize the capsule positioning (Figure b). As the phospholipid polar head groups of the membrane might be in contact with the porous negatively charged capsules in the polar region of the bilayer, cations can migrate in case of 1a through their water‐filled cavities.…”

“…Examples of such approaches include those based on macrocycles, peptides, rigid‐rod β‐barrels, and amphiphiles . The first synthetic lipophilic metallic complex presenting ionic conductance states in a bilayer membrane was reported by Fyles et al, after which Kim et al and Gokel et al demonstrated the efficiency of integrated metal–organic clusters for proton/cation transport across lipid bilayers. Here, we report a new type of synthetic ion‐channel, formed from spherical porous‐type metal‐oxide macroanions [{(Mo VI )Mo VI 5 O 21 (H 2 O) 6 } 12 ­{Mo V 2 O 4 (CH 3 COO)} 30 ] 42− 1a and [{(Mo VI )Mo VI 5 O 21 (H 2 O) 6 } 12 ­{Mo V 2 O 4 (SO 4 )} 30 ] 72− 2a encapsulated by dimethyldioctadecylammonium (DODA + ) cationic surfactants, and showing ionic conductances through bilayer membranes.…”

Artificial Signal Transduction across Membranes

“…For example, ar esorcin [4]arene hemi-channel ( Figure 2C)w as the first to report voltage dependency,w ith ac onductance of % 6pS. [40] Another example are the ion channels built from the tetrameric macrocycle pyrogallol [4]arene, with conductances between 10 and 460 pS, [41][42][43] and the demonstration of chiralselectivet ransport of amino acids through peptide-modified pillar [5 or 6]arenes. [44] Lastly,a na rtificial hemi-channel built from am odified cyclodextrin oligosaccharide macrocycle was reported to selectively transport anionsa cross lipid bilayers, and could also discriminate between halides.…”

Bioinspired Self‐Assembly I: Self‐Assembled Structures

“…Typically, the bilayer can be investigated by conductance measurements in planar bilayers through the voltage-clamp method. For a metallocage with pendant dodecane alkyl groups (12 in Figure 2.8), 75 the measurements showed ion channel behavior toward Na + , K + , and Cs + ions with the greatest selectivity toward Na + . This was consistent with the expected size of the hydrophobic channel presented by the membrane-bound pyrogallole cage.…”